Unveiling atom-photon quasi-bound states in hybrid plasmonic-photonic cavity

作者：Lu, Yu-Wei; Zhou, Wen-Jie; Li, Yongyao; Li, Runhua; Liu, Jing-Feng^*; Wu, Lin^*; Tan, Haishu^*

来源：Nanophotonics, 2022, 11(14): 3307-3317.

DOI：10.1515/nanoph-2022-0162

• atom-photon quasi-bound states
• local density of states
• plasmonic-photonic cavity

Dissipation, often associated with plasmons, leads to decoherence and is generally considered fatal for quantum nonlinearities and entanglement. Counterintuitively, by introducing a dissipative plasmonic nanoantenna into a typical cavity quantum electrodynamics (QED) system, we unveil the wide existence of the atom-photon quasi-bound state (qBS), a kind of exotic eigenstate with anomalously small decay, in the hybrid plasmonic-photonic cavity. To derive the analytical condition of atom-photon qBS, we formulate a quantized two-mode model of the local density of states by connecting the interacting uncoupled cavity modes to the macroscopic QED. With resonant plasmon-photon coupling, we showcase the single-atom qBS that improves the efficiency of single-photon generation over one order of magnitude; and the two-atom qBS that significantly enhances spontaneous entanglement generation compared with a bare photonic cavity. Notably, such single-atom and multi-atom qBS can be simultaneously accessed in realistic plasmonic-photonic cavities, providing a versatile platform for advanced quantum technologies, such as quantum light sources, quantum computation, and quantum information.

• 单位
  华南农业大学; 1; 佛山科学技术学院